The present invention relates to an assembly apparatus and more particularly to an apparatus adapted to assemble elements of rivetless conveyor chain.
The original rivetless chain was the subject matter of U.S. Pat. No. 870,704, Nov. 12, 1907, to Weston. The chain which was the subject matter of the Weston patent is variously referred to as "keystone", "rivetless", or "Weston" chain and has had wide application in conveyor, mining machinery, and other industrial uses. Rivetless chain is strong, adaptable as a sprocket chain, and subject to lengthening or shortening by manually adding or removing individual links of the chain.
Generally speaking rivetless chain consists of alternating units of center links and pairs of side bars joined together by headed pins. Each center link consists of an individual piece of metal having a pair of laterally spaced side walls joined at their ends by curved end walls, said side and end walls enclosing or surrounding an elongated slot. A pair of side bars, each having an elongated slot at each end, is pivotally connected to each end of each center link by headed pins, each pin having a transverse head on each end thereof similar to the headed end of a T-head machine bolt. The side bars are formed at their ends with transversely extending recesses on their outer faces in which the heads of the pins are seated to lock the pins in position after the center links and side bars have been coupled together. Each of the center links has a narrow central portion which tapers outwardly adjacent to the ends of the link to form thickened portions at the link ends. When the center links and side bars are assembled by means of the headed pins to form a chain, the side bars and center links are arranged in alternate relationship along said chain, each center link having connected to each end thereof a pair of spaced side bars and each such pair of side bars being connected at each end to an adjacent center link and so that pivotal movement is permitted between the adjacent center links and side bars about the center of headed pins as an axis.
An improved rivetless chain is disclosed in U.S. Pat. No. 2,507,025, May 9, 1950, to Lemmon which is directed to a center link for rivetless chain having thickened end portions with convexly curved upper and lower faces and a central portion, the upper and lower faces of which are also convexly curved, said curved end portions and central portion of said link being connected by reentrant concave surfaces which merge gradually with said end and central portions without the formation of any sharp lines of demarkation or clevage. The improved center links set forth in the Lemmon patent are commonly used today, and the present invention is particularly well adapted to assemble rivetless chain having such improved center links.
As will be appreciated by those skilled in the art, although rivetless chain enjoys many advantages and is in wide commercial use, the assembly thereof has heretofore been a tedious hand operation with relatively slow assembly speeds and relatively high cost. It would, therefore, be advantageous if the assembly of rivetless chain could be done in an efficient and economical manner by a machine. Thus, in accordance with the present invention, a machine for assembling rivetless chain is provided. While the present machine can be adapted to assemble various types of chain, it is particularly well adapted to assemble rivetless chain as disclosed in the aforementioned Lemmon patent, the disclosure of which is specifically incorporated by reference herein.